This invention relates to an apparatus for inserting weft wire in flat weaving power looms.
German Patent No. 908,240 discloses a weft insertion apparatus wherein a shuttle is disposed within the shed defined by the warp wires. Carriages are guided above and below the shed and drag the shuttle by magnets. These carriages, in turn, are reciprocally driven by a drive means connected thereto.
In the apparatus of the aforesaid patent, the shuttle is further equipped with a weft bobbin so that the shuttle is of large mass and, therefore, requires large acceleration forces. This, in turn, necessitates that the magnets also be large and thus heavy. As a result, the number of picks per minute of the apparatus is limited. Furthermore, at the ends of the path of motion, the shuttle of the apparatus enters shuttle boxes and is no longer under magnetic influence. Mechanical means is therefor additionally needed for better acceleration of the shuttle out of the boxes.
Weft insertion apparatuses are also known in which a shuttle is dragged by only one carriage which is arranged below the shed and is guided by magnetic forces (See, e.g, German Patent No. 211,916 and German published applications (OS) 1,785,147, 2,211,491, and 2,311,780). It is a disadvantage of these arrangements that the shuttle rests directly on the warp wires so that the wires are subjected to forces corresponding to not only the weight of the shuttle but also to the magnetic forces exerted on the shuttle. This is likely to cause damage to the warp wires and high wear of the shuttle.
British patent application No. 2,020,706 discloses a weft insertion apparatus wherein the shuttle is moved through the shed by a linear motor. In this case, in order to avoid excessively high pressing pressure, the stator is divided into two parts between which the shuttle moves. However, when using such a linear motor it is not possible to reach an acceleration sufficiently high to permit a number of picks higher than that reached with mechanical picker means.
It is an object of the present invention to provide an improved apparatus for inserting weft wires so that higher number of picks is attainable.